Integrated management system of grain combine harvester based on Beidou & GPS

At present, most combine harvesters are using Global Positioning System (GPS) to get the position of harvesters and draw harvesters' work trajectories. However, the positioning information might be instable by using a single positioning. In order to solve this problem, this paper makes full use of Beidou/GPS dual-mode receiver which supports positioning and two-way communication. The inside of the Beidou/GPS dual-mode receiver contains 2 positioning systems: Beidou Navigation Satellite System (BDS) and GPS. But these 2 positioning algorithms are using 2 different coordinate systems: Beidou navigation positioning algorithm uses BJ-54 coordinate system, and the positioning algorithm of GPS navigation uses WGS-84 coordinate system. Complementary use of these 2 positioning systems can solve the problem of positioning information instability that occurs when using a single positioning. It means that when the Beidou positioning information has deviation, GPS positioning information can be used to make correction. The combine harvester walking map can be drawn from the positioning information of the Beidou/GPS dual-mode receiver. The message communication function of Beidou satellite is used instead of GSM short message service to realize remote transmission between harvester and control center. The integrated management system for grain combine harvester is designed using sensor detection technology, data acquisition and processing technology, wireless communication technology, navigation technology, speech synthesis technology and computer network technology. The integrated management system of grain combine harvester includes 2 parts: Vehicle subsystems and control center. The vehicle subsystem consists of Beidou/GPS dual-mode receiver, weight sensor module, moisture sensor module, speed sensor module and text-to-speech (TTS) module. The control center consists of clients and server. The vehicle subsystem collects the data of geographical position, harvested area and grain weight, and then transmits the data to the control center by Beidou satellite. The server of control center analyzes and processes these data, and then draws the harvester's work trajectory map and the yield map, and the clients of control center can query the harvester's work trajectory map and the yield map of designated position. In order to achieve integrated management and scheduling for harvesters, the control center can send text commands to the harvesters, and the text commands can be converted into speech through TTS technology. In the field tests, the harvester runs with the speed of 3.6 km/h. The actual area of the harvesting is about 4 716 m2, the actual total mass of grain is 3 086 kg, and the average yield is 6 544 kg/hm2. However, the harvesting area is 4 853 m2, the total mass of grain is 3 193 kg and the average yield is 6 579 kg/hm2 measured by the system. The relative errors are 2.9%, 3.47% and 0.55% respectively. From the result we find that this integrated management system of grain combine harvester has a certain error, but the precisions of harvesting area and grain weight both reach 96%. The tests show the system is running stably and reliably. Therefore, this system is valuable for yield monitoring and trans-regional operation management of grain combine harvester in southern hilly area of China.